TC DEBBIE - 2017

Uncorrected raw data of 1 second wind gusts and barometric pressure on the OCC Weather Station at Airlie Beach
Data courtesy of Campbell Scientific Australia

GENERAL OVERVIEW

Tropical Cyclone Debbie was first mentioned by OCC to subscribers on March 17th (with a larger focus on March 20th) on the Future Aussie Cyclones page and first mentioned to the general public on March 22nd. The Tropical LOW formed on March 23rd and became a Tropical Cyclone on March 26th. TC Debbie became a severe system on March 27th and made landfall around lunch time on March 28th in the vicinity of our chase target Airlie Beach. We observed winds at high-end Category Three intensity across the town while wind speeds approximating a mid-range Category Four were observed officially at Hamilton Island.

THE CHASE

The OCC team agreed to join with South Brisbane Storms chase team to get into TC Debbie. We left Townsville at approximately 4PM on Sunday 26th March and we were planning a chase target of Bowen at the time. We planned to stop at Alva Beach for the night to calibrate instruments with the Alva Beach BoM AWS that night.

At around 11:00AM on Monday 27th March, the team left Alva Beach to go to Bowen. We set up our station at Bowen, but Nitso decided late that afternoon that the team was too far north and the system would drift southward overnight and early the next morning on final approach. The NW eyewall (which Bowen would be located in would likely be the weakest and would offer little benefit for data collection) At 7:00PM we decided to pack up and leave for Airlie Beach. The pack up wasn't completed until around 9:30PM.

We arrived in Airlie Beach a little before midnight to squally winds and heavy intermittent shower activity, the power was already cut to most parts of the town. The road into Airlie was relatively clear with the exception of the odd tree and branches on the road. The trip in was very slow and took us about 2 hours. At around 12:50AM we set up our Campbell Scientific Australia weather station in blinding squally conditions and then headed to our accommodation for some much-needed R and R.

Most of us were awake by around 6:00AM and woke to general Category One type conditions and then decided to go and check our station at around 7:00AM. As we headed out conditions deteriorated only slightly and there were still some breaks in the rain bands where we witnessed squally winds but no blinding rain. Once we made sure the station was setup we quickly traveled around the town showing folks the town live on Facebook. We retreated about half an hour later and had breakfast.

Following brekky, some of the team basically was tied up with radio skype and tv interviews for an hour or so while other members enjoyed some R and R again. Suddenly at around 8:30AM the winds began picking up and Nitso began gathering everyone for the actual trip out for a couple of hours before the eye got too close. The team was out and about until around 10:00AM before it became too dangerous to stay out any longer.

At around midday wind gusts became quite sporadic and it was clear the eye was approaching us as sustained winds had eased. However just as wind gusts had begun dying down, the weather station stopped recording. The team madly went out to seek to recover the station during this much calmer period of weather and thankfully the station was intact, but the soggy ground meant that some of its supports had basically failed due to the mushy ground. We moved the station about a metre or two and re-planted it into the ground before moving around Airlie Beach and having a look at damage associated with the front-end of the system.

We got back inside by around 2:00PM as winds began to increase again from the north. The waves began piling higher and higher beginning around 2:00PM and the peak strength of the system's back-end was felt between 3:00PM and 4:30PM. Thankfully this peak in winds from an onshore direction happened to co-incide with LOW tide and this kept the storm surge to a minimum.

The wind began dying down in the early evening with consistent damaging wind gusts (100+km/hr) but a slow and steady decline in sustained wind speeds was observed. Heavy rain set in after the centre had crossed the coast as the onshore and much moister northerly winds were being forced up along the mountain ranges.

It was a quiet night as the team swapped stories about the system and had a look at each other's footage. As is often the case with these things, once the adrenaline wears off, you can sleep for many hours and most of us got a great night's sleep. The next day we got up and checked the town for damage, there was a fair amount of damage, but most of it was to powerlines and trees. The vast majority of houses survived the cyclone well with us only counting about 5-10 houses with any significant structural damage, and the vast majority of those were due to fallen trees on the houses themselves.

Later that day we decided to pack up and the team began to move out at around mid afternoon. By the evening we were stranded in Bowen as the roads north were cut and had to spend a night there. Thankfully we did because we were treated to one of the best storms and light shows we've seen in North Queensland.

A big thank you also to JCU Cyclone Testing Station and Doctor Henderson who stayed in touch with us through the whole process to ensure we covered the best spots with our combined data collection efforts.